Effect of an o-raffinose cross-linked haemoglobin product on oesophageal and lower oesophageal sphincter motor function

The present experiments evaluate the effects on oesophageal motility of an o-raffinose cross-linked haemoglobin-based oxygen carrier (HBOC) purified f rom outdated donated human blood cells (Hemolink(TM)), with attention to do se-response (0.6-2.4 g kg(-1)), oxygenation status and low molecular weight components (4.4-36.4% 64 kDa or less). In ketamine-anaesthetized cats, low er oesophageal sphincter (LES) function and oesophageal peristalsis were mo nitored 0.5 h before, during and up to 3.5 h after HBOC infusion, and in so me cats at 24 h. (1) All products significantly inhibited LES relaxation an d increased peristaltic velocity in the distal smooth muscle oesophagus, wi thout consistently altering resting LES pressure. (2) Effects on peristalti c velocity reached a maximum at the smallest dose, whereas the effects on L ES relaxation had a maximum effect at 1.2 g kg(-1). (3) Effects were not si gnificantly altered by the haemoglobin oxygenation status or presence of lo w molecular weight components. (4) Repetitive oesophageal contractions occu rred. In the cat, an o-raffinose cross-linked human haemoglobin product produces changes in oesophageal body and LES function, which are independent of the HBOC oxygenation status and composition of the low molecular weight compone nts tested. Changes may persist for at least 24 h. These motility changes a re likely due to scavenging of nitric oxide by the haemoglobin.